Discharge mechanism for dehydrators



April 4, 1950 J. M. HALL 2,503,233

DISCHARGE MECHANISM FOR DEHYDRATORS Filed March 9, 1945 2 Sheets-Sheet 1 IN VEN TOR. 1 wkfose hJl/Lflail WM/GEM/ April 4, 3950 J. M. HALL 2,503,233

DISCHARGE MECHANISM FOR DEHYDRATORS Filed March 9, 1945 2 Sheets-Sheet 2 i I L 5 i 5i, 2 52! 66. 103 65 I 'Hliw i 95 0 67 M390 J hjt i kz Se a 50 72 91 92 By 0 P \7 z 6 WM Patented Apr. 4, 1950 DISCHARGE MECH A NISM FOR DEHYDRATORS .LIosephM. Hall, Chicago, Ill.,.assignor to Drying & Concentrating Company, a corporation of Delaware Application March 9, 1945, Serial No. 581,823

-13-Glaims. vl

In the operation of a dehydrating chamber-of the character here under consideration, a drying medium such as air isxintroduced into-thetchamber through a suitable .inlet and is withdrawn througha suitable outlet inisuc'hmanner asto set up a desired drying circulation in the chamber. Any provision for discharging the dehydrated productfrom the chamber mustnot permitisu'ch communication between the interior and the exterior of the chamber as will interfere with'the required circulation of the drying medium. .-A discharge arrangement "that provides free communication to the atmosphereicannot be usedin most installations since the pressure of'the drying medium in the chamberiseither substantially above or substantially below :atmospheric pressure.

A dehydrator construction "must furthermore meet certain sanitary requirements. All interior surfaces of the dehydrating apparatus that makes contact with the material under process mustbe freely accessible for frequent cleaning and the parts of the system must break down into separate units with smooth material-contacting surfaces sufficiently exposed for thorough and rapid cleaning. In addition, it'is highly desirable that the material under process'be confined to the dehydrating apparatus and "the receptacles for the finished product since leakage or'escapeof the material notonly is costly but also causes unsanitary conditions in the environment of the apparatus.

One object-of my invention 'is to provide an efiicient discharge mechanism constructed to meet the above requirements, that is to say, 'to avoid interferingwith-circulation of thefdrying medium in the dehydratingchamber and to providesanitary operation and permitrapid cleaning. 'In this regard a specific object ofmy inventionisto provide a leakage-proof discharge valve arrangement 01 simple structure that may be quickly dismantled and reassembled. Additional specific objects of the invention relate to the construction of such a valve member per so as will be understood hereinafter.

It is usually desirable 'to;provide 'astirrer to prevent the dehydrated material =fromcaking or banking up in the bottom of "the dehydrating chamber in suchmanneras to block iiowto the discharge valve. A further obj ectof my invention is to provide'such 1a stirrer in combination with adischarge valveandzto providexa common drivinglmeansifor 'both'thelstirreriand the-valve with emphasis :on.1simplicity of structure, :efiicient power transmission, sanitation, and the necessity for periodic dismantling of the apparatus.

My general object is obtained in large part by using a rotary discharge valve lwithoffset inlet and outlet ports, employing an upright shaft directly connecting said valve and the previously mentioned stirrer, and transmitting power .to said shaft between the valve and the stirrer.

Further objects of the invention relateto the construction of the stirrer per se,.it being my purpose to achieve a simplestructurethat effectively a'gltates the dehydratedmaterial and permits'a certainfiexibility with respect to conformation with the configuration of .thedehydratingchamber walls.

The aboveandother objects and advantages 'of my invention will beapparent in the following detailed description taken with "the accompanying drawings.

'In the drawings, which are to be regarded as merely illustrative,

Fig. v1 is a somewhat diagrammatic view of .a dehydrating chamber equipped with my discharge mechanism, the view being largely inisection and partly in side elevation;

Fig. .2 is an enlarged fragmentary :section of thelowerdischarge portion of the dehydrating chamber;

Fig. 3 is a cross-sectionalview taken as indicatedby the line 3-3'0f Fig. 2;

Fig. iis a horizontal'section on a large scale, taken as indicated by the lined- 4 of Fig. 6 with parts broken away to reveal certain structure;

Fig. 5 isa fragmentary section, on a greatly enlarged scale, of the .rotary .valve:.member taken as indicated by the line.55 ofFig. 4; and

Fig.6 is a view on an enlarged scale, :partly in vertical section and partly in sideelevation, of the discharge mechanism.

Fig. 1 shows a dehydrator chamber generally designated H) which may be the sole dehydrating chamber employed or may be merely one unit in a multiple stage system. The dehydrator chamber lfl may be of any shapebut preferably, as indicated in the drawings, is'of circular tapering configuration with a lower restricted discharge portion generally designated H. By way of example, the lower discharge portion 'H is shown of circular tapering configuration :comprising'an upper conical wall l2, an intermediate cylindrical wall l3, a lower conical wall l5, and a lower cylindrical wall l6.

As thus described, .the dehydrating chamber lll'has a bottom opening formedby the lowermost cylindrical wall l6. This bottom opening is to be spanned by a suitable bottom wall removable for cleaning purposes and in the preferred practices of my invention, the bottom wall is a functional part of my discharge mechanism and is removable bodily with an assembly of discharge mechanism parts.

Since the present invention relates primarily to the discharge mechanism, any arrangement may be employed for circulating a drying medium through the dehydrating chamber. In the arrangement shown, the upper end of the dehydrating chamber is provided with an outer cylindrical wall I! of relatively short length and an inner cylinder wall I8 of greater length extending both above and below the inner cylinder wall.

The space between the outer cylindrical wall I! and the inner cylinder wall |8 constitutes an annular inlet passage for the drying medium and the interior of the inner cylinder l8 forms an outlet passage 2| for the drying medium. The lower end portion of the inner cylinder I8 is preferably flared, as indicated at 22, and is spanned by a rotary sprayer generally designated 23 having a central hollow hub or sprayer head 25 and a plurality of hollow arms 26.

The sprayer 23 is preferably of the construction shown and described in my copending application Serial No. 588,467, entitled Dehydrator, filed April 16, 1945. Since the specific construction of the sprayer 23 is disclosed in the copending application and does not constitute a part of the present invention, it is not necessary to go into detail here. It may be noted, however, that the arms 26 are not only hollow to serve as sprayer nozzles, but also are shaped to serve as fan blades to exert an upward propelling force on the drying medium. The sprayer 23 mounted on the lower end of a shaft 21 that extends downward from a motor 28, the shaft being cased in a stationary tube 30. The shaft 2! is of hollow construction so that the liquid material to be dehydrated may be conducted from a suitable supply pipe 3| through the shaft to the sprayer 23.

A suitable drying medium, for example air or superheated steam, is brought to the annular inlet passage 20 by means of an inlet duct 32 and an inlet snail 33 in a well known manner, the snail giving the incoming fiuid stream rotary motion as it enters the chamber. The rotating drying medium moves downwardly through the annular inlet passage in a spiral which expands in diameter to the side walls of the dehydrator -chamber partly because of the flared deflector 22 provided by the inner cylinder l8. The drying medium continues to rotate in the same direction but with increasing velocity as it moves down the progressively restricting walls of the chamber ID. This downwardly moving spiral which may be termed the outer spiral is ultimately reversed in axial direction in the lower discharge portion H of the chamber, and then ascends with the same direction of rotation in what may be termed an inner spiral. In Fig. 1 the outer spiral is indicated by a dot-dash line 35 and the inner spiral is indicated by a solid line. 36.

The inner spiral 36 enters the outlet passage 2| and in doing so is acted upon by the fan-shaped arms 26 of the sprayer 23. From the outlet passage 2|, the drying medium nters an outlet snail 31 from which it is discharged into an outlet duct 38.

Certain additional expedients may be added to facilitate the desired circulation of the drying medium. One such expedient comprises a special deflector generally designated 40 having a central cylinder 4| to which is attached two conical walls 42 and 43. The special deflector 46 is positioned in the region in which the dehydrating chamber i0 narrows to form the discharge portion H, the special deflector being supported in such position by a plurality of suitable brackets 45.

The outer spiral of the drying medium passes downward through the annular spac between the special deflector 46 and the surrounding wall of the chamber I!) while the inner spiral passes upward through the central cylinder 4|.

Another expedient to facilitate the desired circulation may comprise a small auxiliary inlet snail 46 mounted on the conical wall I2 of the chamber discharge portion The auxiliary snail 46 receives a relatively cool fluid medium, for example, air from an inlet duct 41 and discharges the air downward into the chamber portion through an annular inlet port 48. The dehydrated product, for example, powdered milk or powdered egg is heated substantially by the relatively hot drying medium and is usually quite hot when precipitated into the lower chamber portion The introduction of the relatively cool air from the auxiliary snail 46 has a cooling effect to prevent such prolonged heating of the powdered product as might result in deterioration in quality.

'Turning to the details of the present invention, Fig. 6 shows what may be termed a first transverse wall 5| to serve as the bottom of the dehydrating chamber ID, a second transverse wall 52 spaced a substantial distance therebelow to serve as the top wall of a valve casing generally designated 50, and a third transverse wall 53 to serve as the bottom wall of the valve casing. To permit the desiccated material to pass through this assembly, the first transverse wall 5| has an opening 55 constituting the discharge port of the dehydrating chamber ID, the top wall 52 of the valve casing has an inlet opening or port 56, and the bottom wall 53 of the valve casing has a discharge opening or port 51, the latter port being provided with a short spout 60. The discharge port 51 of the valve casing is substantially offset from the inlet port 56 and in the construction shown is at a location diametrical from the location of the inlet port. A passage means or discharge chute 58 interconnects the discharge opening 55 at the bottom of the dehydrating chamber l0 and the inlet port 56 of the valve casing 50.

It is contemplated that the valve casing will be removable with respect to the dehydrating chamber In and preferably the discharge chute 58 is likewise removable. In the construction shown, the top valve casing wall 52, the discharge chute 58, and the bottom wall 5| of the dehydrating chamber are united in one piece that is removably secured to the lower end of the dehydrating chamber. To permit removably mounting this unitary assembly on the lower end of the dehydrating chamber ID, the lower end of the chamber may be formed with a radial flange 6| and the bottom wall 5| of the chamber may likewise be formed with a radial flange 62, the two flanges being normally held together by suitable bolts 63.

It is to be especially noted that dismantling the described construction to separate the unitary assembly of chamber bottom wall 5|, discharge chute 58, and top valve casing wall 52 accomplishes several purposes for facilitating cleaning of the apparatus. In the first place, the removalv of the :unitary assembly-1mm the :chamber '10 leaves: the chamber. completely openv atthebottom to permita thorough flushing operation; 'inithe second place,the removalexposes the inner surface'of thecham'oer bottom .wall.5 l .for cleaning; in the :third place, the whole interior of the discharge chute 58 .isrendered easily accessible .for cleaning and inspection; .in the fourth-place the inner surface of the valvecasing 5.0 iscompletely exposed; .and in the :fifth .place, the interior .of the valve casing .50 .is open .for cleaning and-inspection.

Itv is contemplated that the valve casinglifi will break down further into separate units for cleaning andinspection but willnormally form .a sufiiciently tight construction to prevent release of the desiccated material other than release through the .valveport 51. .In my preferred construction showninthedrawings, the valve casing 5b is completed by a cylindrical wall :E5in the form of a simple ring that is normally clamped between the upper and lower casing walls .52 and .53, which upperand lower casing walls have annular grooves 6% to seat the ring. Normally, the three *walls52, 53 and'85 areheld tightly :together inv assembled relation by suitable means such as a seriesoi bolts 61 equipped with helical springs 58 and wing nuts it. Theseibolts pass through suitable holes in the upper and lower valve casing walls 5.2 and 53 outside the circular wall t5 and the .wing nuts are tightened down sufiiciently to create spring pressure effective for clamping the assembly together.

The valve casing 58 houses a suitable rotary valve member ii that serves to continually push powdered material from. the region inside the valve'casing .56 below the discharge chute 58 to the region above the valve discharge port. In mypreferredconstruction, therotary valve member H is formed with a plurality of arms 72 for acting upon the desiccated material. In my preferred construction, best shown in Figs. 4 and 5, eachof the arms has a face 13 so inclinedqas to have a slight lifting effect on the desiccated material. The inclination of the face '53 also serves to make the lower leading edge 75 of the arm sharper than a rectangular edge to provide an improved scraping action against material that tends to pack by gravitation on the lower valve casing wall 53. moreover, each of the valve arms 12 is'curved or swept back to urge the desiccated material inward from the cylindrical valve wall t5 and-t0 provide a relatively sharp upright leading edge It which tends-to scrape materialfrom the cylindrical wall. It has been found that if the vertical dimension of the valve member H is substantially .003 inch less than the vertical spacing of the two walls 52 and 53, the desiccated material will not be blown past the upper and lower edges of the arm 12 because the powdered material banks across the clearance spaces to form effective seals.

In a dehydrating chamber of the character described, desiccated material such as powdered mill: or powdered egg tends to bank up in the discharge portion M of the chamber instead of flowing freely therethrough, especially since the discharge portion of the chamber is of restricted diameter. It is desirable then to provide the previously mentioned stirrer means to continually break up the powdered mass.

In the construction shown, the stirrer means comprises a plurality of spaced stirrer bars ll of what may be termed Z-shaped configuration and a lowermost stirrer bar l8, U-.shap.ed.in gen- In my preferred construction eral configuration. These various stirrer bars are-mounted on an upright shaftfitzthat slidingly extends through a bearing 8! formed in the transverse bottom wall 5|. A suitable packing means 82 may also be mounted in the trans verse wall 5| to prevent the powdered material from leaking lthrough the clearance space hetweenithe shaft andthe bearing 81 .The lowermost .U-shaped stirrer .bar 18.0011- forms to the dished configuration. of the transverse bottom wall 5! and serves to continually shift-material towards the discharge opening .55 of the-dehydratingchamber as well as to break up the mass-of material immediately above the dischargeiopening. Each of the Z-shaped stirrer ba-rs'lz'iextends radially and diametrically in oppositedirections from'the shait'fiil and has one ofitsends bent upward and the other of its ends bent downwardly, the bent portions conforming tothelocal configuration of the surrounding wall.

:One important advantageoi such a stirrer arrangement is thatit is flexible in the sense that thestirrer bars may be independently bent as required to=avoid scraping contact with the axial wall. .If any one stirrer bar tends to scrape the surrounding wall, it is .a simple matter to bend thestirrer bar in either a vertical plane or a horizontal planetoobviate such contact. If the stirrerbars were interconnected or if individual stirrer .ibars were of braced construction or of considerable dimension axially of the shaft 88, such flexibility would notbe afforded.

While the stirrer arrangement comprises a plurality of stirrer bars, nevertheless the stirrer operation iseifective substantially continuously throughout the vertical dimension of the lower chamber portion :ii. This continuity of the stirring action through substantially the length of thexlowerchambersection ll may be understood by referring to Fig. 6. In Fig. 6, the lowermost stirrer bar 18 createsa zone of stirring operation of the .same vertical height as the U-shaped stirrer. Immediately adjacent this lowermost zone isasecondrzone 'ofxstirring operation represented by the verticaldimension of the downwardly bent portion .83 of the next stirrer bar. Contiguous with this second stirring zone is the third stirring zone corresponding to the upturned portion 8.5 ofzthez'same stirrer bar. The next substantially'contiguous stirring zone is represented by the downwardly bent portion 85 of the'next stirrer bar, and so on.

.In'the provision of a suitable driving means for actuating the .described valve and the described stirrer,it is an object of my invention to meet certain desirable considerations. Among theseconsiderations are the following: the desirability of applying a driving force to the valve and "stirrer, preferably in a balanced manner,

with thepoint of application between the valve and :stirrer; the desirability of constructing a driving connection with the shaft 3% that may betreadily withdrawn'from the shaft in the dismantling procedure, preferably with minimum manipulation; the desirability oi operating the rotaryvalve by means-of the upright shaft in a manner that permits the valve casing-to be withdrawn'from the shaft and yet requires no clearances through which the powdered material mightilea-k from the valve casing; the desirability of providing a power means for driving the shaft '88 that requires little space and does not exert a lateralthrust-tending to throw the lower chamber portion H out of its proper vertical alignment; :and the desirability of minimizing any manipulation for operatively disconnecting the power means when the apparatus is dismantled for cleaning. All of these considerations are satisfactorily met by the construction now to be described.

One important expedient is to employ a small individual motor 8! for actuating the shaft 80 and to mount the motor on a suitable bracket 88 that is unitary with the previously described unitary assembly of transverse bottom wall discharge chute 58 and transverse valve casing wall 52. Thus the motor 81 is movable bodily with the unitary assembly When the unitary assembly is detached from the lower chamber portion II and in normal operation the motor cannot exert a lateral thrust on the lower chamber portion since it is, in effect, carried by the lower portion.

Another important expedient is to actuate the shaft 80 through the medium of a shaft sleeve 90 that extends completely through the valve casing 50 and is releasably engaged with the shaft. In the particular arrangement shown in Fig. 6, the releasable engagement is effected by a suitable cross pin SI that extends through suitable holes in the shaft and shaft sleeve, the cross pin being retained by a cotter pin 92.

The shaft sleeve 90 extends with a suitable close running fit through a bearing 93 in the top casing wall 52 and in the same manner through a suitable close fitting aperture 95 in the lower valve casing wall 53. The valve member II is connected with the shaft sleeve 90 by a suitable key 96 and above the valve casing 50 a rotary driving means in the form of a sprocket gear 9'! is engaged with the shaft sleeve both by a key 98 and a suitable set screw I00. A sprocket chain IOI extends from the sprocket gear 91 to a second sprocket gear I02 on a short drive shaft I03. The drive shaft I03 is part of a speed reduction mechanism I05 operated by the motor 87,

The dehydrated material may be discharged from the spout 60 into any suitable container for the finished product. In the arrangement shown in Fig. 1, however, the spout G0 has an extension in the form of a flexible conduit I04 for discharging the product on to a vibrating screen I06 0perated by a suitable motor IIlI. The screened material passes through a flexible conduit I08 into a shipping container I I0. The shipping container H0 is shown on suitable scales III.

The manner in which the described discharge mechanism operates will be readily understood from the above description. The powdered product produced by dehydration in the chamber I0 gravitates into the discharge portion II of the chamber where it is acted upon by the plurality of stirrer bars to prevent such bridging of the powdered mass as might prevent movement to the bottom of the chamber. In addition, the lowermost U-shaped stirrer bar 78 continuously shifts material at the bottom of the dehydrating chamber towards the entrance to the discharge chute 58. The material dropping down through the discharge chute 58 enters the rotary valve and is continually transferred from the region in the valve casing below the discharge chute to the region above the spout 60.

As may be understood by referring to Fig, 4, the arms 72 of the valve member II are effective successively to block communication between the inlet and outlet ports of the valve casing 50, the powdered material itself serving as a seal across all clearance spaces. As a result, there is no possibility of such gaseous flow between the atmosphere and the interior of the lower dehydrating chamber I I through the valve casing 50 as would interfere with the dehydrating operation or undesirably reduce the pressure differential between the dehydrating chamber and the atmosphere. All of the assembled parts, including the parts of the valve casing 50, are leakage-proof so that no material escapes from the apparatus except through the spout 60.

The frequent dismantling of the discharge mechanism for cleaning may be carried out in a rapid and convenient manner to make all of the material-contacting interior surfaces readily accessible for cleaning. It is merely necessary to remove the series of bolts 63 around the bottom of the chamber portion I I and to remove the cross pin 9| from the lower end of the shaft to permit bodily removal as a unit of the assembly comprising the chamber bottom wall 5|, the discharge chute 58, the rotary valve, the motor and the driving connection between the motor and the valve. It is to be noted that upon such removal of the assembly the interior of the dehydrating chamber I0 becomes readily accessible for cleaning and flushing. All the surfaces within the dehydrating chamber including the surfaces of the stirrer means are smooth and free from such crevices as would tend to trap the dehydrated material.

The assembly that is bodily removed in the manner described may itself be quickly broken down into members and sub-assemblies that are designed for thorough and convenient cleaning. It is merely necessary to remove the bolts 6'! and the associated springs 68 to permit removal of the I bottom wall 53 and the cylindrical wall 65 of the valve casing 50 thereby to expose all of the interior valve surfaces. When the valve casing 50 is dismantled in this manner, a sub-assembly remains intact including the following elements: the discharge chute 5B; the top valve casing wall 52; the sprocket gear 9? the speed reduction mechanism I05; and the motor I01. It is to be emphasized that the motor drive presents no problem whatsoever in the dismantling procedure and does not make necessary any additional dismantling operation. It is a feature of the invention that the simple procedure of removing the bottom wall of the dehydrating chamber results in operatively disconnecting the power means from the upright shaft 80 and leaves the shaft exposed in the lower end of the dehydrating chamber for cleaning.

The description herein, in specific detail, of a preferred practice of my invention suggests the possibility of various changes and substitutions under my concept and I reserve the right to all such departures from the description that properly fall within the scope of my appended claims.

I claim:

1. In a dehydrating system, a dehydrating chamber, a bottom wall for said chamber, a valve casing including a top easing wall spaced below said bottom wall, said valve casing having a discharge port, an upright shaft extending through said chamber bottom wall and said valve casing, passage means interconnecting said two walls for communication between said chamber and said casing, said passage means lying to one side of said shaft, said valve casing being removable relative to said dehydrating chamber, stirrer means in said chamber actuated by said shaft, a sleeve journalled in said valve casing, said sleeve surrounding said shaft and being slidable longitudinally of the shaft, a rotary valve in said casing operatively connected with said sleeve, a rotary drive means on said sleeve outside said ego-capes valvecasing to drive saidsl'eeve andshaft thereby to drive said stirrer and valve, power means operatively connected with said rotary drive means foractuation thereof, and means releasably securing said sleeve on said shaft whereby release of saidsecuring 'means' will'permit bodily movement of said sleeve'together with said valve casing and saidrotary drive means away from said chamber.

2. In a dehydrating system, a dehydrating chamber, a bottom wall for said chamber, a valve casing including a top casing wall spaced; below said bottom wall, said valve casing havinga discharge port, an upright shaftextending through said chamber bottom wall and said valve casing, a passage means interconnecting said two walls for communication between said chamber and said valve casing, saidpassage means lying to one side of said shaft; said valve casing and said passage means being removable relative to said dehydrating chamber, stirrer means in said chamber actuated by said shaft, a sleeve rotatably mounted in said top casing wall, said sleeve surrounding-said shaft and being slidable' relative to the shaft, said sleeve, being releasably connected with'the shaft, a rotary valve mounted on said sleeve inside said casing, and arotary drive mean mounted on said sleeve outside said casing, said valve casing sleeve and rotary drive means being movable with said sleeve when the sleeve is shifted downward along said shaft.

3.111 a dehydrating system, a dehydrating chamber, a bottom wall for said chamber, a first releasable means normally anchoring said'bottom wall in place, stirrer means in said chamber, a rotary valve for discharging the dehydrated material from said chamber, said rotary valve including a valve casing connected to saidbottom.

wall, a sleeve for actuating said valve, a power driven shaft operatively connected" with said stirrer, said shaft extending through said sleeve, and a second releasable means-connecting'said sleeve to said shaft whereby-release of both said releasable means permits opening of said chain.- ber by bodily'movement of the-assembly comprising said bottom wall, said valvecasing, andlsaid sleeve.

4. In a dehydrating system, a dehydrating chamber open at the bottom, a first transverse wall removably connected to said chamber across the bottom opening thereof, a second transverse wall spaced below said first transverse wall, passage means interconnecting said two walls to provide communication with said chamber through said second wall, a third transverse wall spaced below said second transverse wall, said third wall having a discharge port out of register with said passage means, an upright cylindrical wall between said second and third transverse walls, means to hold said cylindrical wall and said second and third transverse walls in asseroled positions to form a closed cylindrical, valve casing, said holding means being releasable for separation movement of the walls to expose for cleaning operation the inner surfaces of the valve casing and of the lower end of said passage means, a rotary valve in said valve casing to move dehydrated material therein from the region below said passage to the region above said discharge port, a shaft for actuating said rotary valve means, said shaft extending upward through said first and second transverse walls to one side of said passage means, stirrer means in said chamber actuated by said haft, and power means lb, operatively connected to the shaft intermediate said first and second transverse walls.

5. In a dehydrating apparatus, a dehydrating chamber, a bottom wall for said chamber separated from the rest of the chamber structure, a valve-casing having a discharge port, a top wall for said casing separate fromthe rest of the casing structure, an upright shaft extending through both said chamber bottom wall and said top casing wall, a passage means interconnecting said two walls for communication between said chamber and said valve casing, said passage means lying to one side. of said shaft, means securing said bottom chamber wall to the rest of the chamber structure and securing said top casing wall to. the rest of the casing structure, said securing means being releasablev whereby the bottom chamber wall may be lowered away from the rest of the chamber structure and the rest of the casing structure may be lowered away from said top" casing wall thereby to expose for cleaning operations the inner surfaces of said two walls. and said passage means as well as the interiors of said chamber and valve casing, stirrer means in said chamber actuated by said shaft, and drive means operatively connected to said'shaft.

6. In adehydrating apparatus, a dehydrating. chamber,- a bottom wall for. said chamber separated from the restof the chamber structure, a valve casing'having. a discharge port, a top wall for'said casing separate from the rest of the casing structure, an upright shaft extending through,

both said chamber bottom wall and said top casing wall, a passage means interconnecting said v two walls for communication between said chamber and said valve casing, said passage means lying to one side of said shaft, means securing said bottom chamber'wall'to the rest of the chamber structure and securing said top casing wall tothe rest of' the casing structure, said securing means being releasable whereby the bottom chamber wall may be lowered away from the rest of the chamber structure and the rest of the casing structuremay be lowered away from said top casing wallithereby to expose for cleaning operations the inner surfaces of said two.

walls and said passage means as well as the interiors of said chamber and valve casing, stirrer means in said chamber actuated by said shaft, and power means carried by said valve casing, said power means being operatively connected with said shaft between said bottom chamber wall and said top casing wall.

7. In a dehydrating apparatus, a dehydrating chamber, a passage means extending downward from the bottom of said chamber, a valve casing mounted on the lower end of said passage means, said passage means and said valve casing constituting a conveying assembly to move dehydrated material out of said chamber, a shaft to one side of said passage means extending upward into said chamber and downward into said casing, stirrer means in said chamber driven by said shaft, a rotary valve member in said casing driven by the shaft, a motor mounted on said conveying assembly, said motor being operatively connected with said shaft, and means securing said conveying assembly to said chamber, said securing means being releasable to permit the conveying assembly together with the motor to be lowered into spaced relation to the chamber to expose the interior of the chamber and the interior of said passage means for cleaning.

8. In a dehydrating apparatus, a dehydrating chamber, a passage means extending downward from the bottom of said chamber, a valve casing mounted on the lower end of said passage means, said passage means and said valve casing constituting a conveying assembly to move dehydrated material out of said chamber, a shaft to one side of said passage means extending upward into said chamber and downward into said casing, said shaft having an intermediate portion exposed outside said passage, stirrer means in said chamber driven by said shaft, a rotary valve member in said casing driven by the shaft, a motor mounted on said conveying assembly, said motor being operatively connected with said intermediate portion of the shaft, and means securing said conveying assembly to said chamber, said securing means being releasable to permit the assembly together with the motor to be lowered into spaced relation to the chamber to expose the interior of the chamber and the interior of said passage means for cleaning.

9. In a dehydrating apparatus, a dehydrating chamber, a passage means extending downward from the bottom of said chamber, a valve casing at the lower end of said passage means, said valve casing having an upper wall united with said passage means for movement therewith, a shaft to one side of said passage means extending upward into said chamber and downward into said casing, said shaft having an intermediate portion exposed outside said passage, stirrer means in said chamber driven by said shaft, a rotary valve member in said casing driven by the shaft, a motor operatively connected with said intermediate portion of the shaft, said motor being united with said passage means for movement therewith, and means securing said passage means to said chamber, said securing means being releasable to permit the passage means together with the motor to be lowered into spaced relation to the chamber to expose the interior of the chamber and the interior of said passage means for cleaning.

10. In a dehydrating apparatus of the type wherein a substantial pressure difierential is maintained between the interior pressure and atmospheric pressure, a dehydrating chamber having a port therein for discharge of desiccated material, an inclosed valve chamber having inlet and outlet ports therein, a passage between said discharge port of said dehydrating chamber and said inlet port, a rotary valve in said valve chamber adapted for continuous transfer of said desiccated material from said inlet port to said outlet port without substantial loss of said pressure differential, and means for operating said rotary valve.

11. Apparatus as described in claim 10, having stirring means in said dehydrating chamber, said stirring means being operatively connected to said rotary valve.

12. In a dehydrating apparatus of the type wherein a substantial pressure differential is maintained between the interior pressure and atmospheric pressure, a dehydrating chamber having a port therein for discharge of the desiccated material, an inclosed valve chamber having inlet and outlet ports therein, a passage between said dehydrating chamber and said inlet port, a rotary valve in said valve chamber, said rotary valve being smaller than said valve chamber to provide clearance between said valve and said chamber, said clearance being on the order of .003 of an inch whereby said valve will transfer said desiccated material from said inlet port to said outlet port without substantial loss of said pressure differential, and drive means for operating said rotary valve.

13. Apparatus as described in claim 12, having stirring means in said dehydrating chamber, said stirring means being operatively connected to said rotary valve.

JOSEPH M. HALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 217,436 Weaver July 8, 1879 266,700 Langlois Oct. 31, 1882 1,444,648 Willis Feb. 6, 1923 2,089,534 Carlson Aug. 10, 1937 2,207,822' Rooney July 16, 1940 

